This application claims priority of Japanese Patent Application No. 2004-070903, filed on Mar. 12, 2004, in the Japan Patent Office, the disclosure of which is incorporated in its entirety by reference.
1. Field of the Invention
The present invention relates to an electrically operated vehicle drive controller, an electrically operated vehicle drive control method and its program.
2. Background Art
A planetary gear unit having a sun gear, a ring gear and a carrier is conventionally arranged in a vehicle drive unit mounted to a hybrid type vehicle as an electrically operated vehicle and transmitting one portion of the engine torque as torque of an engine to an electric generator (electric generator motor) and transmitting the remaining engine torque to a drive wheel. The above sun gear and the electric generator are connected to each other. The ring gear, a drive motor and the drive wheel are connected to each other. The carrier and the engine are connected to each other. Driving force is generated by transmitting the rotation outputted from the above ring gear and the drive motor to the drive wheel.
In the hybrid type vehicle of this kind, when the engine is driven in accordance with an engine target rotating speed that is a target value of the engine rotating speed as the rotating speed of the engine, the engine torque becomes ring gear torque as torque of the ring gear and appears in the ring gear, and is transmitted to the drive wheel. An insufficient amount of the ring gear torque with respect to torque required to run the hybrid type vehicle, i.e., vehicle request torque, is compensated by drive motor torque as torque of the drive motor.
Therefore, electric generator torque as torque of the electric generator is calculated on the basis of the above engine target rotating speed. Electric generator target torque that is a target value of the electric generator torque is converted into a value on the ring gear and the ring gear torque is calculated. This ring gear torque is further converted into a value on the output shaft of the drive motor, and the drive shaft torque is determined. On the other hand, the above vehicle request torque is converted into a value on the output shaft of the drive motor, and output shaft request torque is determined. The difference between this output shaft request torque and the drive shaft torque is set to drive motor target torque that is a target value of the drive motor torque.
In this case, when the ring gear torque is calculated on the basis of the electric generator target torque and the drive shaft torque is determined, the influence of inertia torque as torque of an inertia (inertia of a rotor and a rotor shaft) amount of the electric generator at a changing time of the electric generator torque appears in the ring gear torque. Therefore, the ring gear torque is calculated by expecting the inertia torque, and the drive shaft torque is determined.
However, in the above conventional vehicle drive unit, an angular acceleration of the electric generator is required to calculate the inertia torque of the electric generator. However, it is necessary to differentiate the rotor position of the electric generator detected by a resolver twice to calculate this angular acceleration. When a periodic change is generated in the rotor position by the characteristics of the resolver, dispersion is generated with respect to the calculated angular acceleration so that an error is generated in the inertia torque of the electric generator.
Accordingly, an error is also generated in the drive shaft torque determined on the basis of the inertia torque, and an error is further generated in the drive motor target torque. Accordingly, it is impossible to stably run the hybrid type vehicle.
Therefore, sending the angular acceleration to a limiter and removing an excessively large value and an excessively small value by this limiter has been considered. However, this dispersion of the angular acceleration can not be removed and the vehicle drive unit can not be stably operated.